Python statistics.stdev() Method

Example

Calculate the standard deviation of the given data:

# Import statistics Library
import statistics

# Calculate the standard deviation from a sample of data
print(statistics.stdev([1, 3, 5, 7, 9, 11]))
print(statistics.stdev([2, 2.5, 1.25, 3.1, 1.75, 2.8]))
print(statistics.stdev([-11, 5.5, -3.4, 7.1]))
print(statistics.stdev([1, 30, 50, 100]))

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Definition and Usage

The statistics.stdev() method calculates the standard deviation from a sample of data.

Standard deviation is a measure of how spread out the numbers are.

A large standard deviation indicates that the data is spread out, - a small standard deviation indicates that the data is clustered closely around the mean.

Tip: Standard deviation is (unlike the Variance) expressed in the same units as the data.

Tip: Standard deviation is the square root of sample variance.

Tip: To calculate the standard deviation of an entire population, look at the statistics.pstdev() method.

Syntax

statistics.stdev(data, xbar)

Parameter Values

Parameter	Description
data	Required. The data values to be used (can be any sequence, list or iterator)
xbar	Optional. The mean of the given data. If omitted (or set to None), the mean is automatically calculated

Note: If data has less than two values, it returns a StatisticsError.

Technical Details

Return Value:	A `float` value, representing the standard deviation of the given data
Python Version:	3.4

❮ Statistic Methods